I've configured an OpenVPN client on my OpenWrt router using the luci-app-openvpn plus some additional modifications to /etc/config/firewall to implement a "kill switch" (routes all traffic through VPN).
Somehow, my DNS traffic is still being routed to my ISP's servers. Before modifying /etc/config/firewall to implement the kill switch, I was not experiencing these DNS leaks.
Can someone help explain how this is occurring, if you know. I can send any config files needed. My VPN provider is ProtonVPN.
Thanks for the help.
EDIT: I've tested the DNS leak with 2 different laptops, and I find that my DNS leaks while using only one of them. The laptop that leaks is a Qubes OS machine with a browser open in a Fedora VM.